91 lines
1.9 KiB
Go
91 lines
1.9 KiB
Go
package pipebootstrap
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import (
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"flag"
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"io"
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"os"
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"time"
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"github.com/hashicorp/consul/command/flags"
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"github.com/mitchellh/cli"
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)
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func New(ui cli.Ui) *cmd {
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c := &cmd{UI: ui}
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c.init()
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return c
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}
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type cmd struct {
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UI cli.Ui
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flags *flag.FlagSet
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help string
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}
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func (c *cmd) init() {
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c.help = flags.Usage(help, c.flags)
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}
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func (c *cmd) Run(args []string) int {
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// This should never be alive for very long. In case bad things happen and
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// Envoy never starts limit how long we live before just exiting so we can't
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// accumulate tons of these zombie children.
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time.AfterFunc(10*time.Second, func() {
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// Force cleanup
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if len(args) > 0 {
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os.RemoveAll(args[0])
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}
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os.Exit(99)
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})
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// Read from STDIN, write to the named pipe provided in the only positional arg
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if len(args) != 1 {
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c.UI.Error("Expecting named pipe path as argument")
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return 1
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}
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// WRONLY is very important here - the open() call will block until there is a
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// reader (Envoy) if we open it with RDWR though that counts as an opener and
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// we will just send the data to ourselves as the first opener and so only
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// valid reader.
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f, err := os.OpenFile(args[0], os.O_WRONLY|os.O_APPEND, 0700)
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if err != nil {
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c.UI.Error(err.Error())
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return 1
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}
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_, err = io.Copy(f, os.Stdin)
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if err != nil {
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c.UI.Error(err.Error())
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return 1
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}
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err = f.Close()
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if err != nil {
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c.UI.Error(err.Error())
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return 1
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}
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// Removed named pipe now we sent it. Even if Envoy has not yet read it, we
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// know it has opened it and has the file descriptor since our write above
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// will block until there is a reader.
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c.UI.Output("Bootstrap sent, unlinking named pipe")
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os.RemoveAll(args[0])
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return 0
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}
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func (c *cmd) Synopsis() string {
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return synopsis
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}
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func (c *cmd) Help() string {
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return c.help
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}
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const synopsis = "Internal shim for delivering Envoy bootstrap without writing to file system"
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const help = `
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Usage: should only be used internally by consul connect envoy
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`
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